Electrolytic cell and method of maintaining the efficiency thereof.



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l APPLICATICNHLBD 1350.17, 1912. l l 1,056,181,a Patented 1121111211913.

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` W. M. JEWBLL.

ELCTRCLYTIC CELL AND METHOD OF MAINTAINING THE EFFICIENCY THEREOP.V

APPLICATION FILED DEC.17, 1912.

1,05 @91 @l m Patented Mar. 18, 1913.

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ATTORNEYS.

ciently to preserve the desired stratication.

the horizont-al type,

UNITED STATES Parmi onnicn.

WILLIAM M. JEVJELL, OF CHICAGO, ILLINOIS, 4ASSIGN'OR T0 CIELO-RIDE PROCESS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

EL-ECTROLYTIC CELL AND METHOD OF MAINTAINING THE EFFICIENCY THEREOF.

Specification of Letters Patent..

Patented Mar. 18, 1913.

Application filed December 17, 1912. Serial No. 737,164.

To ZZ fte/mm t may conc-em:

Be it known that I, WILLIAM M. JnwimL,

a citizen ofthe United-States, residing .at Chicago, in the county of Cook and State of illinois, have invented certain new and useful Improvements in Electrolytic Cells and Methods of Maintaining the Ther-cof, of which the following is a specilication, reference being had to the accompanying drawings. A

My invention relates to electrolytic cells of and more particularly to that type in which the electrolyte is separated, so to speak, into different strata by reason of the different density thereof, at different levels, or in different zones. Many attempts have heretofore been made to produce an electrolytic cell ofthis type would maintain a high degree of efficiency, but so far as I am aware, they have not been successful, except to a limited extent. In a cell of this character I have found that it is highly important to maintain the anode liquor at a high degree of density, while the cathode liquor' should be comparatively light as in that way the efficiency of the cell is increased, but heretofore in the practical op eration of gravity cells where the anode and cathode liquors are, in a sense, separated by the difference in their specific gravities, and not by the use of a diaphragm, as the oper# ation ot' the cell continues, the anode liquor becomes spent and the cathode liquor gradually becomes heavier, owing to its taking into solution some ofthe products of the decomposition of the electrolyte, so that in a com-A paratively short time the cathode liquor bev ing the heavier sinks to the bottom of the cell. I have discovered that the obstacles heretofore encountered due to a heavier cathode liquor lmay be overcome and the eiliciency of the cell'be constantly maintained at a satisfactory point by placing the anode in the lower portion of the cell and. the cathode in a relatively higher position, and maintaining the cathode liquor at all times at a lower state of density than the anode liquor, so that a stratification of the electrovte that is the reverse of the usual horizontal cell stratification is preserved while the cell is in operation. The desired difference in density is secured by adding to the cathode iiquor a suitable liquid, such as water. which will act to lighten the cathode liquor suiii- Efficiencywhich This-liquid may be-added either constantly, or from time to time, during the operation of the cell as may be necessary to maintain the cell at its highest efficiency. I also provide means between the anode and cathode for collecting and removing the gases liberated at the anode. My invention is particularly advantageous in connection with cells, the purpose of which is to generate chlorin, or other gases, by decomposition of the electrolyte.

My improved cell, as illustrated in the drawings and as hereinafter described, provides formaintaining the maximum strength of the anode liquor ntwithstanding its decomposition, and for conducting awayv the liquid, as well as the gaseous products of the electrolyt-ic action.

In the accompanying drawings in which I have illustrated two forms of cells embodying my invention, Figure l is a longitudinal vertical section on line 1 1 of Fig. 2; Fig. 2 is a horizontal'section on line 2 2 of Fig. l, the principal parts of the cell being, however, shown in plan view; Fig. 3 is a cross-section on line 3 3 of Fig. 2, the salt replenishing tank being partly broken away; Fig. 4 is a partial vertical section illustrating a modification; Fig. 5 is a partial plan View of the construction shown in Fig. 4; and Fig. 6'is a vertical cross-section on line 6 6 of Fig. 4.

Referring to the drawings, 7 indicates a tank or receptacle of suitable shape and dimensions, which is made of soap stone, or other suitable material. The cell shown in Figs. 1 to 3 is composed of two similar units, but it will be noted that the cell may comprise one or more units as desired. In the' construction shown in said figures, the r`eceptacle 7 is divided transversely near the y center by two partitions 8 9 set a short distance'apart, forming an intermediate chamber l0, into which the chlorin, or other gas liberated at the anodes, is conducted, and from which the anode liquor is replenished, as hereinafter described. The chamber l0 is inclosed by la cover-plate 11, Which `overlies the partitions 8 9 and the sidesA of the receptacles 7, as shown in Fig. 2. Near its ends l2 13, the receptacle 7 is also provided with transverse partitions l4 15, set a short'distance from their respective ends of the receptacle, and between said partitions andthe adjacent er is is a horizontal iid partition 16, `orming upper and lower chambers 17T-18, at the ends ot the receptacle, as shown in Fig. 1. 'the chambers 1'? receive the etlluent ot the cathode liquor and the chambers 13 receive the etlluent ot the anode liquor, as hereinat'tcr described. 19-20 indicate the compartments between the partitions ---l-l and .tl-m15, respectively, as illustrated in lig. 2.

Tf1 indicates the anodes, which are preterab` it icheson graphite, and which are arranged longitudinally in the lower portionsl ot the compartiments 19H20 and extend through the partitions Svi) into the collecting chamber 10. ln the illustration, said apodosy are shown as formed trom cylindrical rods ot graphite which are cut down, except at their inner ends, into the term ot slabs, the rounded inner ends ot said anodes being preferably screw-threaded, so that they may be connected by bus bars 22, located in the collecting chamber 10, and rising through the cover 1.1 thereof, so that they may be conveniently connected to positiveterininals 23, as shown in Fig. 1. rl`he anodes 21 are placed nearthe bottom ot the receptacle i", resting at their ends upon suitable supports, such as cross-bars 2-l-2 5, locates at the ends ot thev compartments 19h20, as shovtn in ltigs. 2 and rlhese cross-ba s may be ot any suitable inert material.

26 indicates inverted troughs, which ea:- tend trom end to end ot the compartments 19-20, over the anodes therein, their ends resting on the supports 2dr-25. Said troughs are to eonline the gases liberated at the anode and direct them to the collecting chamber 10, with which they communicate, through openings 27, which are located near the upper portions otsaid troughs, as best shown in lT ig. 3.

23 indicates additional openings between the collecting chamber and the space beneath the troughs Q6, which may be termed the anode chambers, said openings serving to admit the replenished solution. to said chambers, as hereinafter described.

2) indicates the cathodes, which are usually made ot iron, and in the construction illustrated are in the torni ot comparatively thin ttm-shaped bars. They are arranged in the compartments 19-520, extending trom end to end thereoll at a higher level than the anodes, as shown in Fig. 3. fis therein shown, the cathodes rest at their ends on supporting blocks 30, which rest on the cross-bars 24--5, but they may b'esupported in any other suitable vvay.

31 indicates bolts which connect the several cathodes together, so that the several cathodes ot each unit maybe connected to a common negative terminal 32, as shown in Fig. 1. t

33 indicates passaees in the partitions intensi le which connect the anode chambers to the compartments 13, said passages being arranged at aboutvthe'upper level ot the anode liquor in said anode chambers. rilhe purpose ot said openings is to permit the spent brine to flow from the anode chambers into the compartments 18.

indicates pipes Which lead trom the compartments 18 to the inlet pipe 35 ot a pump 36, which may be driven in any suitable way. 37 indicates a pipe leading from the outlet ot' said pump to the lower port-ion ot a tank 38, adapted to contain salt, or equivalent material, for restoring the strength ot the electrolyte. The upper rportion ot the tank 38 is connected by a pipe ,l0 'with the upper port-ion otl the collecting chamber l0, as shown in Fig. 2, so that the anode liquor passing into the compartments 13 may be circulated by the pump 36, through the tank 38, and .back to the collecting chamber 10, from which `it may again pass into the anode chambers, through the passages 28. rlhe tank 38 is provided near one end with a transverse partition 39, which rises to the level atA which it is desired to maintain the liquid in the tank 38, such level being somewhat higher than the outlet 40, so that the head ot brine maintained in the tank 33 by the partition 39, determines the iow ot brine through the pipe l0 into the collecting chamber 10. ein overdoiv chamber 39a is provided at the opposite side ot the partition 39, which chamber communicates by a pipe 41 With the inlet ipe 35 ot the pump, so that any brine over ,owing the partition 39 Hows backto the pump, through the pipe l-l. i

i2 indicates a pipe leading from the upper portion et the compartment 39, which is closed by a cover 43, to the collecting chan,- ber 10, :tor conducting any chlorin gas therein to said collecting chamber.

del indicates an opening in the cover 43, through which air may be admitted to the tank 38, and 45 indicates an overflow outlet at the upper portion of the compartment 39% 46 indicates pipes tor supplying Water, or other liquid, to the compartments 19-20, outside of the trough 26, for diluting the cathode liquor.

di' indicates a :tunnel through which brine l is supplied to the collecting chamber, tor distribution to the several anode chambers, and t3 indicates a pipe for supplying brine to said tunnel, as shown in Fig. 1.

t9 indicates a chlorin outlet pipe which communicates with the upper portion ot the collect-ing chamber 10, as shown in .F ig. 1 for conducting away the chlorin generated.

El he operation ofthe cell 'shown in Fi s. 1, 2 and 3 when used to generate chlorin trom a brine electrolyte is as tolloivs :"Jllhe cell is supplied with brine.j a suitable liquid, such as Water, beingsupplied to the upper The desired level of tion of the cell, so that the liquor surrounding the anodes is heavier than that surrounding the cathodes, the proper diierence in density being maintained by the admission of the lightening liquid either continuously or from time to time, as may be required. During the passage of the current through the cell chlorin is liberated at the anodes and sodium hydrate is formed at the cathodes, the chlorin being conducted by the troughs 26, to the collecting chamber l0, whence it passes out through pipe 49. The spent anode liquor is discharged through the outlet 33, to the compartment 18, whence it may pass through pipes 34 to the pump 36 and is then forced through pipe 37 to the compartment 38, where it takes up a fresh .Supply of salt and then passes back into the collect-ing chamber l0, and through it back to the anode chambers, through passages 28. the cathode liquor is maintained in the cell by overow into the compartment 17, through slots 50, in the partit-ions l4-l5, as best shown in Figs. l and 2, whence it may be conducted away through loutlets 5l.

The .provision of means for introducing fresh brine int-o `the circulating electrolyte, as described, is an important factor in the efficiency of the cell, since the brine so supplied to the circulating anode liquor passes to a certain extent under the edges of the troughs and 'up to the cathode liquor. By this means the anode liquor of the cell is entirely changed in a certain period of operation, such period depending upon the volume of the brine feed and the anode contents of the cell. Thus the accumulation in the anode liquor of chlorates, or other obj ectiona'ble products of the electrolytic action, is prevented. In a cell of the type shown in Figs. l, 2 and 3 of the drawings, using 500 amperes of current, the brine feed may run from 75 c. c. to 150 c. c. per minute, and in such a cell the anode liquor contents would thus be displaced and renewed in less than each twenty-four hours of operation.

It will be noted that as best shown in Fig. 3, the anodes are at a lower level than the cathodes, so that by maintaining the difference in density, as described, .the proper stratification of the electrolyte may be at all times maintained, with the result that the cell may be maintained constantly at a high degree of eiiciency, regardless of the .length of time during which it is in operation. The feed of water, or other liquid, to the cathode liquor is approximately the same in quantity as that of the brine feed above referred to.

lVhere the cell is used with an electrolyte the decomposition of which does not tend to make the cathode liquor heavier, so that the operationof the cell does not disturb the I stratiicatiomit is not usually necessary to add a lightening liquid to the cathode liquor.

In Figs. et, 5 and 6, I halve shown a differ,- ent form of cellin which the same results may be secured by Vmaintaining the necessary stratification of the electrolyte as hereinbefore described. ln the modified construction l employ a cell 52, which is preferably rectangular in form, and is separated by transverse partitions 5S into a series of transversely -arranged compartments. The upper portion of the cell is further divided transversely by a series of partitions 54, which extend from the upper portion of the cell downward, butterminate a short distance from the bottom of the cell, as vshown in Fig. 4, thus providing a series of anode chambers 55, alternating with a. series of cathode chambers 56. The anode'chambers are closed at the top by cover-plates 57. 58 indicates a series of electrodes, preferably rods of graphite, or other suitable material, which extend through the several partitions 53 and the endsof the cell, as shown in Fig. l, but present a greater surface to the Cathode chambers than to the anode chambers. These rods may be paraflined or otherwise treated to preventv vthe passage of the electrolyte through them by capillary attraction. By connecting the end elec` t-rodes with the poles of a battery, or other suitable source of current, the several rods become anodes and cathodes arranged respectively in the anode and cathode chamf bers. In this .construction the requisite stratification is maintained by supplying water, or other lightening liquid, to the cathode chambers, through pipes 59. The chlorin generated in the anode chambers escapes through pipes- 60, communicating with th upper portions of said chambers, and

.connecting with a header 6l, as shown in Fig. 5. Thesodium hydrate formed in the cathode compartments escapes through pipes 62, to troughs G3, through which it may beconducted away. Brine is supplied to the anode chambers and causedA to circulate by pipes 64, which communicate with the several anode chambers at about the upper level of theanode liquor, and with an inlet header 65, provided with a funnel 6G, or other suitable means for supplying fresh brine thereto. The brine passes out of the anode chambers through pipes 67, said pipes communicating with a header 68. The several partitions 53-54 may be made of any suitable dielectric material and are prefer` ably soapstone and glass, respectively. It will be understood that the same means for circulating and regenerating the anode liquor as shown in Figs. 2 and 3, may be used in lconnect-ion with this construction also. In this connection I wish to say that while in my improved construction the use of a diaphragm for the purpose of maintaining the separation ofthe anode and cathode liquors is usually unnecessary, my invention 'swosorvmg stratihat of the anode liquor.

The mohod of maintaining the e'- snoj of an elecroyfc Coll of the horizona yg/pa which @omissis in preserving sirmixozion of Eno anofle and czhode lquols by g Upyng :l Suitable lqlld 'lio the Comodo quol o koop s specific glzwly lowe than mi of -he anode quor.

8, The meho@ of mauianug the si?? @muy o'f an eldecolynic cell of 'the horizonzd Jij/po having mode and cmhode l'qllofs.l l i L le :modo hquof and a L noo o quo, which con' Il@ liquid to mais f5 g Fawlty than die liquor.

in sup- Lodo hqowfes:

o of the horzon- 

